Supplementary data:

Abstract

The observed geomorphology and calculated thermal histories of the Bhutan Himalaya providean excellent platform to test ideas regarding the influence of tectonics and climate on the evolution of aconvergentmountain range. However, little consensus has been reached regarding the late Cenozoic history ofthe Bhutan Himalaya. Some researchers have argued that observed geologic relationships show slowingdeformation rates, such that the range is decaying from a geomorphic perspective, while others see the rangeas growing and steepening. We suggest that a better understanding is possible through the integratedinterpretation of geomorphic and thermochronometric data from the comparison of predictions from modelsof landscape evolution and thermal-kinematic models of orogenic systems. New thermochronometric datathroughout Bhutan aremost consistent with a significant decrease in erosion rates, from2 to 3 km/Ma down to0.1–0.3 km/Ma, around 6–4Ma. We interpret this pattern as a decrease in rock uplift rates due to the activationof contractional structures of the Shillong Plateau, an uplifted region approximately 100 km south of Bhutan.However, low-relief, fluvial landscapes throughout the Bhutanese hinterland record a late pulse of surface upliftlikely due to a recent increase in rock uplift rates. Constraints from our youngest thermochronometers suggestthat this increase in rock uplift and surface uplift occurred within the last 1.75Ma. These results imply thatthe dynamics of the Bhutan Himalaya and Shillong Plateau have been linked during the late Cenozoic, withstructural elements of both regions active in variable ways and times over that interval.